The present invention relates to polarizing lenses for attachment to existing spectacles already having polarizing lenses thereon so that by varying the position of the attached polarizing lenses, the transmission of light through the lens may be varied. In the past it has been common to provide spectacles having polarizing lenses in sunglasses to reduce the transmission of light through the lenses of the glasses to the eyes of the wearer. The polarizing lenses not only reduces the transmission of light, but reduces certain types of glare and reflections reaching the eyes of the wearer. It has also been suggested in the past to use spectacles having a pair of polarizing lenses for each eye mounted adjacent to each other, with one lens being rotable, generally by hand-fingers to vary the density through a pair of lenses, thereby varying the transmission of light therethrough. These prior art variable density spectacles have been manufactured and sold in small quantities, but have not gained wide popularity due to the wide variations in styles and tastes in spectacles and eyeglasses, and especially in sunglasses demanded. Typical prior art patents might be seen in the Schwartz U.S. Pat. No. 3,838,913 and the Archambault Pat. No. 2,813,459. One patent to Evans, U.S. Pat. No. 3,236,579 teaches a vacuum cup attachment for sunshading lenses while the Zingarelli U.S. Pat. No. 3,890,037, teaches spectacle frames with a removable tinted lens for converting ordinary spectacles to sunglasses by the attachment of a tinted flexible plastic lens which is frictionally engaged with a frame portion. The present invention overcomes many of the prior art problems by providing polarizing lens attachments for mounting to existing standard sunglasses having polarizing lenses which are rotable so that pairs of polarizing lenses are adjacent to each other, with one being rotatable to vary the density through the two lenses. Since the attachments are adapted to be placed upon a variety of sunglasses, a purchaser may select any type of sunglasses desired and then have the variable density feature added to the glasses as an option.